Ultrassonografia de alta frequência na avaliação de bioestimuladores de colágeno: estudo com ácido poli-L-láctico e hidroxiapatita de cálcio.

Abstract

The human skin is divided into three layers: epidermis, dermis, and hypodermis. The dermis is composed of collagen and elastin fibers permeated by subcutaneous tissues and blood vessels. It also contains structures such as hair follicles, sebaceous glands and sweat glands. This layer plays a key role in body temperature regulation and immune responses. Skin aging is influenced by intrinsic factors (such as hormonal changes during menopause) and extrinsic factors (such as ultraviolet radiation from sunlight), leading to various alterations, including reduced dermal thickness and compromised collagen fiber integrity. In recent decades, there has been an increase in studies on aging, particularly facial aging. These studies showed that aging population seeks for aesthetic care, such as daily use of sunscreen use and the pursuit of both invasive and non-invasive aesthetic procedures. In this context, collagen biostimulators are widely used, with the most common formulations being poly-L-lactic acid (PLLA) and calcium hydroxyapatite (CaHA). Their mechanism involves inducing collagen synthesis through a secondary inflammatory response, and thus, an increase in dermal thickness is the outcome. High-frequency ultrasound (HFUS) enables the visualization of the skin and the differentiation of its layers. This study aimed to evaluate the increase in dermal thickness resulting from he stimulation of neocollagenesis caused by collagen biostimulators composed of PLLA and CaHA through evaluation using HFUS. A prospective longitudinal analytical observational cohort study was conducted with 32 female patients who received collagen biostimulator treatment with PLLA (Group 1 - 14 participants) and CaHA (Group 2 - 18 participants). The thickness of the dermal layer in the right preauricular region was monitored using a LOGIQ e (GE Healthcare) ultrasound device with a high-frequency linear probe of 18 and 22 MHz. Measurements were taken before the procedure and at 30, 60, 90, and 120 days post-treatment. The study found that both formulations of collagen biostimulators were safe and effective in increasing dermal thickness in the evaluated region. HFUS with a 22 MHz transducer was effective in measuring this skin layer and detecting the progressive increase in dermal thickness during the follow-up period. No significant difference was observed between the effects of the two biostimulators, with 60 days marking the peak of dermal thickness increase.